scholarly journals Change in Electric Contact Resistance of Low-Voltage Relays Affected by Fault Current

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2166 ◽  
Author(s):  
Andrzej Ksiazkiewicz ◽  
Grzegorz Dombek ◽  
Karol Nowak
Keyword(s):  
Contact Resistance ◽  
Contact Surface ◽  
Low Voltage ◽  
Short Circuit ◽  
Current Phase ◽  
Fault Current ◽  
Electric Contact ◽  
Switching Cycle ◽  
Electric Contacts ◽  
The Impact

Contact resistance is an important maintenance parameter for electromagnetic switches, including low-voltage relays. The flow of significant current through electric contacts may influence the contact surface and thus the value of the electric contact resistance (ECR). The change in ECR is influenced not only by the value of current but also by the current phase. Therefore, the impact of the switching short-circuit current’s phase on the ECR was analyzed in this paper. Significant changes in the resistance after each switching cycle were observed. The ECR decreased significantly after each make operation, and a correlation with current amplitude, total let-through energy, and short-circuit time was not observed.

scholarly journals Implementation and Experimental Verification of Smart Junction Box for Low-Voltage Automotive Electronics in Electric Vehicles

2020 ◽  
Vol 10 (7) ◽  
pp. 2214
Author(s):  
Sang Wook Lee ◽  
Soo-Whang Baek
Keyword(s):  
Electric Vehicles ◽  
Printed Circuit Board ◽  
Pulse Width Modulation ◽  
Low Voltage ◽  
Short Circuit ◽  
Circuit Board ◽  
Area Network ◽  
Automotive Electronics ◽  
Overload Protection ◽  
The Impact

In this study, we designed and implemented a smart junction box (SJB) that was optimized for supplying power to low-voltage headlights (13.5 V) in electric vehicles. The design incorporated a number of automotive semiconductor devices, and components were placed in a high-density arrangement to reduce the overall size of the final design. The heat generated by the SJB was efficiently managed to mount an Intelligent Power Switch (IPS), which was used to power the headlights onto the printed circuit board (PCB) to minimize the impact on other components. The SJB was designed to provide power to the headlights via pulse width modulation to extend their lifetime. In addition, overload protection and fail/safe functions were implemented in the software to improve the stability of the system, and a controller area network (CAN) bus was provided for communications with various components in the SJB as well as with external controllers. The performance of the SJB was validated via a load operation test to assess the short circuit and overload protection functions, and the output duty cycle was evaluated across a range of input voltages to ensure proper operation. Based on our results, the power supplied to the headlights was found to be uniform and stable.

scholarly journals Fault Assessment and Mitigation of the 132kV Transmission Line in Nigeria using Improved Resonant Fault Current Limiting (RFCL) Protection Scheme

2018 ◽  
Vol 3 (10) ◽  
pp. 38-44
Author(s):  
D. C. Idoniboyeobu ◽  
S. L. Braide ◽  
Wigwe Elsie Chioma
Keyword(s):  
Power System ◽  
Transmission Line ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Resonant Circuit ◽  
Fault Current ◽  
Protection Scheme ◽  
Current Limiting ◽  
Simulation Results ◽  
The Impact

This research work proposed an improved Resonant Fault Current Limiting (RFCL) protection scheme to reduce the impact of three-phase short-circuit faults in a power system sub-transmission network. The model used an interpolator-extrapolator technique based on a Resonant Fault Current Limiter (RFCL) for automating the procedure of predicting the required reactor value that must be in resonant circuit to limit the short-circuit current values to permissible values. Using the developed model, short-circuit fault simulations on the three phases of the transmission line (Phase A-C) were performed in the MATLAB-SIMULINK environment. Simulation results were obtained by varying the resonant inductance (reactor) parameter of the RFCL circuit for each of the phases to obtain permissible short-circuit current levels and the values used to program a functional interpolator-extrapolator in MATLAB; the resonant values were typically set to values of inductance equal to 0.001H, 0.01H and from 0.1H to 0.5H in steps of 0.1H. Simulation results revealed the presence of very high short-circuit current levels at low values of the resonant inductor. From the results of simulations, there are indications that the RFCL approach is indeed very vital in the reduction of the short circuit current values during the fault and can safeguard the circuit breaker mechanism in the examined power system sub-transmission system. In addition, lower fault clearing times can be obtained at higher values of inductances; however, the clearance times start to converge at inductance values of 0.1H and above.

scholarly journals Robust Fault Protection Technique for Low-Voltage Active Distribution Networks Containing High Penetration of Converter-Interfaced Renewable Energy Resources

Processes ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 34 ◽  
Author(s):  
Shijie Cui ◽  
Peng Zeng ◽  
Chunhe Song ◽  
Zhongfeng Wang
Keyword(s):  
Renewable Energy ◽  
Low Voltage ◽  
Short Circuit ◽  
Renewable Energy Sources ◽  
Distribution Network ◽  
Distribution Networks ◽  
Fault Current ◽  
Fault Protection ◽  
High Penetration ◽  
Small Fault

With the decentralization of the electricity market and the plea for a carbon-neutral ecosystem, more and more distributed generation (DG) has been incorporated in the power distribution grid, which is then known as active distribution network (ADN). The addition of DGs causes numerous control and protection confronts to the traditional distribution network. For instance, two-way power flow, small fault current, persistent fluctuation of generation and demand, and uncertainty of renewable energy sources (RESs). These problems are more challenging when the distribution network hosts many converter-coupled DGs. Hence, the traditional protection schemes and relaying methods are inadequate to protect ADNs against short-circuit faults and disturbances. We propose a robust communication-assisted fault protection technique for safely operating ADNs with high penetration of converter-coupled DGs. The proposed technique is realizable by employing digital relays available in the recent market and it aims to protect low-voltage (LV) ADNs. It also includes secondary protection that can be enabled when the communication facility or protection equipment fails to operate. In addition, this study provides the detail configuration of the digital relay that enables the devised protection technique. Several enhancements are derived, as alternative technique for the traditional overcurrent protection approach, to detect small fault current and high-impedance fault (HIF). A number of simulations are performed with the complete model of a real ADN, in Shenyang, China, employing the PSCAD software platform. Various cases, fault types and locations are considered for verifying the efficacy of the devised technique and the enabling digital relay. The obtained simulation findings verify the proposed protection technique is effective and reliable in protecting ADNs against various fault types that can occur at different locations.

Analysis of the Impact of Distributed Generation on Distribution Network Protection

2012 ◽  
Vol 433-440 ◽  
pp. 5924-5929 ◽  
Author(s):  
Jie Dong ◽  
Ya Jun Rong ◽  
Chun Jiang Zhang
Keyword(s):  
Distributed Generation ◽  
Theoretical Basis ◽  
Short Circuit ◽  
Distribution Network ◽  
Relay Protection ◽  
Fault Current ◽  
Protection Scheme ◽  
Network Protection ◽  
The Impact ◽  
Short Circuit Condition

With the connection of distributed generation (DG), structure of traditional distribution network changes and original relay protection scheme should be adjusted. On the basis of introducing the concept and advantages of distributed generation, this paper discusses the influence of distributed generation with different position or different capacity on current protection. The paper analyzes magnitude and distribution of fault current under short-circuit condition and change curves of fault current are given, which provides some theoretical basis for new relay protection scheme.

scholarly journals Simulation Test of a DC Fault Current Limiter for Fault Ride-Through Problem of Low-Voltage DC Distribution

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1753 ◽  
Author(s):  
Bing Han ◽  
Yonggang Li
Keyword(s):  
Fault Detection ◽  
Low Voltage ◽  
Short Circuit ◽  
Distribution Network ◽  
Fault Current ◽  
Fault Current Limiter ◽  
Dc Fault ◽  
Fault Ride Through ◽  
Current Limiter ◽  
Short Circuit Fault

The low voltage direct current (LVDC) distribution networks are connected with too many kinds of loads and sources, which makes them prone to failure. Due to the small damping value in the DC lines, the fault signal propagates so fast that the impact current with the wave front of millisecond and the transient voltage pose great challenges for fault detection. Even worse, some faults with small currents are difficult to detect and the communication is out of sync, resulting in protection misoperation. These problems have severely affected the new energy utilization. In view of this, a DC fault current limiter (FCL) composed of inductance, resistance, and power electronic switch was designed in this paper. The rising speed of fault current can be decreased by the series inductance and the peak value of the fault current can be limited by series impedance, thus in this way the running time can be gained for fault detection and protection. For distributed energy access, by deducing the short circuit fault characteristic expression of LVDC distribution network, the feasibility of FCL was verified. Based on the structure of the bridge-type alternating current (AC) current limiter, the structure and parameters of the DC FCL were determined according to the fault ride-through target. Then, a low voltage ride-through strategy based on DC FCL was proposed for the bipolar short-circuit fault of LVDC distribution network. Finally, MATLAB/Simulink simulation was used to verify the rationality of the proposed FCL and its ride-through strategy.

Short-Circuit Current Criterion under Condition of Protection Action in Low Voltage Power Supply System

2013 ◽  
Vol 860-863 ◽  
pp. 1914-1918
Author(s):  
Yi Rong Su ◽  
Jie Yu ◽  
Jun Liu ◽  
Gan Zhou ◽  
Li Ping Zhan ◽  
...  
Keyword(s):  
Power Supply ◽  
Power Supply System ◽  
Low Voltage ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Supply System ◽  
Circuit Breakers ◽  
Level Of Automation ◽  
Current Criterion ◽  
The Impact

In order to improve the level of automation and security of the low voltage power supply system, this paper proposed the calculation method of short-circuit current criterion under condition of protection action. Firstly, the impact of circuit breakers on the short-circuit current is analyzed. Then, the current criterion under condition of short-circuit protection are given. Finally, using a special case, the calculation process of aforementioned current criterion is given in detail.

scholarly journals Assessing the impact of front grid metallization pattern on the performance of silicon solar cells

2021 ◽  
Author(s):  
Saba Siraj ◽  
Sofia Akbar Tahir ◽  
Adnan Ali
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Contact Resistance ◽  
Silicon Solar Cell ◽  
Fill Factor ◽  
Short Circuit ◽  
Research Work ◽  
Maximum Efficiency ◽  
Silicon Solar Cells ◽  
The Impact

Abstract The aim of this research work was to assess the impact of front and rear grid metallization pattern on the performance of silicon solar cells. We have investigated the effect of front grid metallization design and geometry on the open-circuit voltage (Voc), short circuit current density (Jsc), fill factor (FF) and efficiency (ŋ) of silicon solar cells by using Griddler 2.5 simulation program. We used different number of metal fingers ranging from 80–120 having width of 60 µm and different number of busbars ranging from 1–5 busbars on the front and rear side of solar cells for optimization. We have also calculated the efficiency and fill factor at different values of front contact resistance ranging from (0.1–100) mohm-cm2, front and rare layer sheet resistances ranging from (60–110) ohm/sq and different edge gaps. We found that the maximum efficiency and fill factor was obtained with those parameters, when front and rare contact resistances were taken as same. We have designed an optimized silicon solar cell with 115 number of fingers, 4 busbars, front and rare contact resistance of 0.1 mohm-cm2 and front and rare layer sheet resistance of 60 ohm/sq. In this way we were able to successfully optimize the silicon solar cell having efficiency and fill factor of 19.49 % and 81.36 % respectively, for our best optimized silicon solar cell.

scholarly journals Fault Analysis using SFCL in the Convertor System at the Load Line

2021 ◽  
pp. 60-67
Author(s):  
Suman Baghel ◽  
Sanjeev Jarring
Keyword(s):  
Large Scale ◽  
Low Voltage ◽  
Control Strategies ◽  
Short Circuit ◽  
Renewable Energy Sources ◽  
Short Circuit Current ◽  
Fault Analysis ◽  
Residual Current ◽  
Operating Conditions ◽  
The Impact

Among many renewable energy sources, solar energy is considered one of the most promising resources for large-scale electricity generation. Here propose resistive SFCL if a fault occurs in a simple low voltage (LV) network. To assess the impact of SFCL in the power system under study, the space-time approach is used to evaluate the short-circuit current in force and spurious control strategies are suggested to achieve the goal. The results complement the feasibility of the proposed A-ACO-based rationalization control for transmission activity according to the limiting circuit and fault current analyzer. The second model of the bastard chassis concludes that the chassis with residual current limiting circuit and analyzer reduces the expansion of the residual current and prevents the voltage from dropping to zero, that no artificial and temporal innovation is used as before. Intelligence-based computer procedures further shorten the working time, which also makes the frame more efficient, as the voltage is restored to its typical value in a short time if the test frame is played for 1 second in a MATLAB climate / SIMULINK. The time taken by the ACO algorithm to restore normal operating conditions in the line was 0.197 seconds, 0.206 seconds and 0.27 seconds for LLLG, LLG and LG errors, respectively.

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